For example, in devices corresponding to a transmission standard of a digital signal, such as PCIe Gen 4.0, USB 3.0/3.1, or Thunderbolt, which is a measurement target of an error rate measurement apparatus, characteristics of a test board for each transmission standard are evaluated, and thus it is necessary to introduce an ISI calibration channel, which is a test fixture simulating a specified transmission line loss, to the input to the test board.
However, a loss amount of the ISI calibration channel varies depending on a transmission standard. For this reason, a user needs to prepare a loss board of the ISI calibration channel which conforms to a transmission standard, apart from the test board for each transmission standard. Additionally, in preparing the loss board of the ISI calibration channel, troublesome work is caused in which a loss value of loss board is actually measured and it has to be evaluated whether a target loss value is obtained, which has laid a burden on the user.
Incidentally, there has also been desire for performing evaluation by adding not only a loss due to the above-mentioned ISI calibration channel but also emphasis, in evaluating characteristics of a test board for each transmission standard.
As a technique for adding emphasis, for example, an emphasis optimization apparatus disclosed in Patent Document 1 is known. According to the emphasis optimization apparatus, it is possible to bring emphasis close to an optimum value in setting a tap width and an intensity value (modulation amount) for each tap.